Geocaching is a high-tech treasure hunting game played throughout the world by adventure seekers equipped with GPS devices. The basic idea is to locate hidden containers, called geocaches, outdoors and then share your experiences online. Geocaching is enjoyed by people from all age groups, with a strong sense of community and support for the environment.
Here's a link to the main global geocaching website: http://www.geocaching.com/ although there are others.
To use this website fully you need to register with a team name or nickname. Registration is free and allows you to log in, see the cache coordinates, to log your visits and upload photographs. There is also a premium membership with a small fee which allows you access to other facilities, such as 'Pocket Queries' (where you can download all the caches in a area in a single file) but this is not absolutely necessary for the casual geocacher.
It even possible to find some caches without a GPS receiver, as the description and hint gives enough information to locate the container.
